1. Field of the Invention
This invention relates to novel calixarene derivatives and to the use of such derivatives for sequestration of metals, particularly transition metals including precious metals. The invention also concerns a process for selectively sequestering transition metals from aqueous mixtures of alkali metals and transition metals, as well as a process for regenerating the calixarene derivative from its complex with the transition metal.
2. Description of Related Art.
U.S. Pat. No. 4,556,700 Harris et al describes the use in adhesive compositions of calixarene compounds represented by the forumla ##STR2## where R.sup.1 is alkyl, alkoxy, substituted alkyl or substituted alkoxy; R.sup.2 is H or alkyl; and n=4, 6 or 8.
McKervey et al., J. Chem. Soc. Commun. 1985 p. 388 describes the cation transfer properties of Alkyl Calixaryl acetates. These ester calixarenes are only capable of sequestering alkali metals or alkali metals together with transition metals.
Olmstead et al., J. Am. Chem. Soc., 1985, 107, 8087-8091, describe complexes of p-tert.-Butylcalix[4]arene with the transition metals Titanium (IV), Iron (III) and Cobalt (II).
Izatt et al, J. Am. Chem. Soc., 1985, 107, 63-66 describe cation transport from multiple alkali metal cation mixtures using a liquid membrane system containing a series of calixarene carriers, specifically p-tert.-butylcalix[4]arene, - calix[6]arene, and -calix[8]arene and p.-tert.-pentylcalix[4]arene, -calix[6]arene and -calix[8]arene.
Yokota et al, Makromol, Chem., Rapid Commun., 5, 767-770 (1984) describe polymers with thiacrown ether units which are more effective in binding metal ions such as Cu.sup.2+, Ni.sup.2+, CO.sup.2+ and Hg.sup.2+ than in binding alkali metal ions.
Kimura et al., J. Chem. Soc., Chem. Commun., 1985, 1041 describe a macrocyclic dioxotetra-amine which acts as a carrier for the membrane transport of CU.sup.2+ ions.
Izatt et al., J. Am.Chem. Soc., 1983, 105, 1785-1790 describe macrocyclic ligand carriers which showed transport selectively for Ag.sup.+ --M.sup.n+ binary cation mixtures in a H.sub.2 O--CHCl.sub.3 --H.sub.2 O liquid membrane system. Selection of macrocycles having appropriate combinations of oxygen with either nitrogen, or sulfur donor atoms led to selective transport of Ag.sup.+ in preference to any of the other cations studied.